• Journal of Korean Neurosurgical Society
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• 제66권4호
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• pp.476-481
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• 2023

Objective : The latest version of the Leksell Gamma Knife Icon^TM allows for mask- and frame-based fixation. Although mask fixation provides fractionated treatment and immobilization using a noninvasive method, it is not free from collision. The authors investigated the collision problem with a modified mask fixation method. Methods : This study presents a case of two meningiomas in the frontal area, where a collision occurs in the occipital area. A modified mask fixation method was introduced to avoid the collision : first, the edges of the head cushion were cut off and polystyrene beads with a diameter of approximately 5 cm were removed. Next, the head cushion was sealed using a stapler. Finally, the head cushion was flattened in the adapter. We compared the shot coordinates, 3-dimensional (3D) error, clearance distance, and vertical depth of the head cushion between the initial and modified mask fixations. Results : When comparing the initial and modified mask fixations, the difference in the shot coordinates was +10.5 mm along the y-axis, the difference in the 3D error was approximately 18 mm, and the difference in clearance was -10.2 mm. The head cushion was approximately 8 mm deeper in the modified mask fixation. Conclusion : Based on these findings, we recommend a modified mask fixation method for gamma knife radiosurgery using ICON with a collision.

• 감성과학
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• 제7권2호
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• pp.123-131
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• 2004

본 연구는 하회탈이 갖고 있는 감성적 요인에 대해 알아보고 문화상품과 관련한 제품디자인 개발에 도움이 되고자 시도되었다. 하회탈 이미지 평가를 위해 감성 형용사 어휘 32개를 추출하여 분석한 결과 첫째, 32개의 감성 평가 어휘로 하회탈 이미지에 대해 알아본 결과, '매력성', '향토성', '흥미성', '역동성', '정교성'의 5개 요인이 나타났다. 둘째, 하회탈 종류에 따라 향토성과 흥미성에서 감성 차이가 있었다. 특히 양반탈이 초랭이탈보다 향토성이 강하며, 중탈, 백정탈 및 부네탈보다는 흥미성이 더욱 높은 것으로 나타났다. 셋째, 하회탈 상품의 재질에 따라 정교성에서 감성 차이가 있었고, 특히 유리 재질에 대해 정교한 이미지를 가지고 있었다. 넷째, 하회탈의 감성이미지는 인구통계학적 특성(나이, 성별, 학력)과 제품 특성(재질, 탈 종류)에 영향을 받고 있었다. 본 연구를 토대로 향후 하회탈 관련 문화상품 개발시 5가지 감성적 요인을 고려한다면 소비자의 니즈에 부합하는 제품 디자인 개발이 이루어질 것이다.

• 대한치과교정학회지
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• 제26권5호
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• pp.547-556
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• 1996

본 연구는 성장기의 골격성 III급 부정교합 환자에서 face mask를 이용하여 상악골을 전방 견인하였을 때, 골격 및 치아관계와 연조직 측모의 변화를 관찰하고 face mask사용전후의 경조직과 연조직 변화의 유의성을 검정하여 상악골 열성장을 보이는 골격성 III급 부정교합 환자의 진단과 치료계획 수립에 도움을 주고자 하였다. 서울대학교병원 치과진료부 교정과에 내원하여 상악골 열성장에 의한 골격성 III급 부정교합으로 진단받고 face mask를 사용하여 양호한 치료결과를 보인 환자 15명을 대상으로 face mask사용전후 두부 방사선 계측사진을 촬영하고 face mask 사용전 계측치와 face mask사용후의 계측치를 분석하여 다음과 같은 결과를 얻었다. 1. SNA와 상악골의 실제 길이인 Co-A가 통계적으로 유의한 수준으로 증가하여(p<0.001), 상악골은 face mask에 의한 치료후 상당량 전방위치 되었다. 이는 face mask의 orthopedic effect에 의한 것이다. 2. 상, 하악골의 실제길이를 나타내는 Co-A, Co-Gn이 face mask 사용후 모두 유의성있게 증가하였다(p<0.01). 3. 하악골의 위치는 상당량 후하방 회전되었다. FMA(p<0.001), SN-GoGn(p<0.01), Y-axis(p<0.01) 등이 face mask 사용후 유의성있는 증가를 보였다. 4. 상악전치, 하악전치의 face mask사용후 치축의 경사도는 유의성있는 차이를 보이지 않았다. 5. 연조직에 대한 변화에서 상순의 위치가 전방으로 변화하여 정상적인 측모의 평균치에 가깝게 변한 것이 인정되었다(p<0.01).

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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• pp.221-222
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• 2000

The vibration of a mask degrades the color purity in CRT. In order to reduce the vibration. a damping wire is put into contact with the mask in the Flatron. We analyzed the vibration of the mask considering the damping wire using FEM. The natural frequencies and mode shapes of the mask are calculated by modal analysis. And those are compared with the measured results to confirm our finite element model. The modal analysis of the wire is also performed to investigate resonance with the mask. Finally, the transient dynamic analysis of the mask contacting with the wire is performed. The vibration of the mask is measured to confirm our analysis, and the results are in good agreement with the analysis.

• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2371-2376
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• 2021

As the γ-ray energy increases, a reconstructed image becomes noisy and blurred due to the penetration of the γ-ray through the coded mask. Therefore, the thickness of the coded mask was increased for high energy regions, resulting in severely decreased the performance of the detection efficiency due to self-collimation by the mask. In order to overcome the limitation, a modified uniformly redundant array γ-ray imaging system using dual anti-mask method was developed, and its performance was compared and evaluated in high-energy radiation region. In the dual anti-mask method, the two shadow images, including the subtraction of background events, can simultaneously contribute to the reconstructed image. Moreover, the reconstructed images using each shadow image were integrated using a hybrid update maximum likelihood expectation maximization (h-MLEM). Using the quantitative evaluation method, the performance of the dual anti-mask method was compared with the previously developed collimation methods. As the shadow image which was subtracted the background events leads to a higher-quality reconstructed image, the reconstructed image of the dual anti-mask method showed high performance among the three collimation methods. Finally, the quantitative evaluation method proves that the performance of the dual anti-mask method was better than that of the previously reconstruction methods.

• 한국전기전자재료학회논문지
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• 제21권2호
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• pp.111-117
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• 2008

We have studied surface roughness, contamination of impurity, bonding with some gas element, reflectance and zeta potential on masks to be generated or changed during photolithography/dry or wet etching process. Mask surface roughness was not changed after photolithography/dry etching process. But surface roughness was changed on some area under MoSi film of Cr/MoSi/Qz. There was not detected any impurity on mask surface after plasma dry etching process. Reflectance of mask was increased after variable plasma etching treatment, especially when mask was treated with plasma including $O_2$ gas. Blank mask was positively charged when the mask was treated with Cr plasma etching gas($Cl_2:250$ sccm/He:20 $sccm/O_2:29$ seem, source power:100 W/bias power:20 W, 300 sec). But this positive charge was changed to negative charge when the mask was treated with $CF_4$ gas for MoSi plasma etching, resulting better wet cleaning. There was appeared with negative charge on MoSi/Qz mask treated with Cr plasma etching process condition, and this mask was measured with more negative after SC-1 wet cleaning process, resulting better wet cleaning. This mask was charged with positive after treatment with $O_2$ plasma again, resulting bad wet cleaning condition.

• 한국통신학회논문지
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• 제11권4호
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• pp.280-286
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• 1986

행렬분해에 의하여 edge검출용 mask operator의 고속계산법을 제시하였다. 다방향성 mask operator의 각방향에 대한 계산결과는 mask원소와 화상간의 곱한 것을 합산한 것이다. 이것은 각 mask의 원소를 행으로 하는 행렬과 mask에 포함되는 화소를 원소로하는 벡터와의 곱과 마찬가지여서 1차원 신호변환으로도 취급할 수 있다. 본 논문에서는 Sobel 및 Prewitt operator의 경우에 대한 변환행렬을 구한 다음 분해하여 계산량을 산출하여 직접 계산할 때의 방법과 비교하였다. 이 결과 여분의 기억점을 사용치 않고서도 이 방법에 의한 계산량은 Soble 및 Prweitt operator의 경우에 각각 직접 계산량의 42.86%, 50%밖에 되지 않았다. 그리고 100x100화소의 화상인 경우에 301개의 여분의 기억점을 사용할때에 Sobel opreator는 직접 계산량의 35.93%로 줄어 들었다.

• 대한통합의학회지
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• 제7권3호
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• pp.85-94
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• 2019

Purpose: The purpose of this study was to observe the degree of mask contamination in dental hygienist for general and oral bacteria and to identify areas of mask contamination after treatment. Methods: Masks were collected with every fifty dental hygienists who currently working in the department of preventive dentistry, prosthodontics, and orthodontics in Busan. The mask bacteria were collected in specific upper and side parts of the mask. Hand germs were collected using sterile cotton swabs, and then placed in a sterile conical tube. These were transferred to the laboratory. Hand germs and mask bacteria were incubated with nutrient broth (NB) and brain heart infusion broth (BHI) for 24 hrs and each cultured with NB and BHI plate at $37^{\circ}C$ for 48 hrs. Collected data were analyzed using the SPSS Window 20. Results: The number of bacteria was observed in the order of the department of preventive dentistry ($10.1{\times}10^5CFU/ml$), prosthodontics ($14.7{\times}10^5CFU/ml$), and orthodontics ($23.3{\times}10^5CFU/ml$) in the hand. In general bacteria, the difference of contamination was seen by the parts of the mask, but there was no significant difference. However, the oral bacteria were observed highly contaminated upper part of the mask in preventive dentistry. The mask contamination according to the medical departments was observed. Especially, the contamination of mask in preventive dentistry was significantly higher than other departments in oral bacteria. Conclusion: This study suggested that correct mask replacement and recognition of contamination areas can contribute to the prevention of infectious disease. and it would be necessary to increase hand hygiene performance to prevent cross-infection with masks. Also, this study may give an idea for making guidelines for mask management and supporting to establish clear criteria for the education program of personal protective equipment.

• 복식문화연구
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• 제2권2호
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• pp.265-282
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• 1994

The mask used in drama has been reappreciated, and it needs profound and systematic studies in order to form the mask to effective use. In research, the aesthestic values in the masks of he latter period of Chosun(the mideighteenth century-the early nineteenth century) was examined through the analysis of traditional drama in accordance with the historical social background. In the later period of Chosun, the active performance of the mask in company with the occurrence of a popular movement caused by people's self-awakening showed a close relationship between the development of the mask and its historical background the moulding characteristic of the mask was analysed before and after the eighteenth century, and regionally in the south and in the middle and the north. The mask express the quality of art before he eighteenth century. It showed, on the other hand, a strong social nature and a touch of satires on society in the south and a religional interest in he middle and the north. This study shows from the viewpoint of a aesthetics that traditional Korean mask during Chosun period had comfortable and voluminous forms with beauty curved lines and colors and rhythm. The aesthetic values in mask as expressed through the aesthetic characteristics have been classified the beauty of nature the beauty of personality, the beauty of traditions. Visual image with these beauty in masks were expressed into fashion illustration of suits and dresses.

• 한국정밀공학회지
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• 제25권1호
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• pp.138-144
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• 2008

Micro-machining of a brittle material such as glass, silicon, etc., is important in micro fabrication. Particularly, micro-abrasive jet machining (${\mu}-AJM$) has become a useful technique for micro-machining of such materials. The ${\mu}-AJM$ process is mainly based on the erosion of a mask which protects brittle substrate against high velocity of micro-particle. Therefore, fabrication of an adequate mask is very important. Generally, for the fabrication of a mask in the ${\mu}-AJM$ process, a photomask based on the semi-conductor fabrication process was used. In this research a rapid mask fabrication technology has been developed for the ${\mu}-AJM$. By scanning the focused UV laser beam, a micro-mask pattern was fabricated directly without photolithography process and photomask. Two kinds of mask patterns were fabricated using SU-8 and photopolymer (Watershed 11110). Using fabricated mask patterns, abrasive-jet machining of Si wafer were conducted successfully.